1. Field of the Invention
The present invention relates to battery cases, and in particular, to a battery case having plate sections fixed to each other by a fixation member.
2. Description of the Related Art
JP-A-2007-200758 discloses a metal case (battery case) in which cells are stored. The metal case includes a case body (battery case body) and a cap plate (cap body) that are joined each other by screws, as well as a sealing member provided between the case body and the cap plate. Further, JP-A-2007-200758 also describes that the case body is made of a material such as iron or aluminum. In this case, as welding an aluminum material is difficult as compared to a material such as iron, a case body made of an aluminum material is often provided by jointing the material using fixation members such as rivets.
However, as compared to welding, forming a case body by jointing a material using fixation members is susceptible to gaps, and thus provides lower sealing functionality. Consequently, a problem of failing to ensure high sealing functionality of the case body is envisaged. Especially, in the aerospace fields, safety against leakage of organic electrolyte solutions of nonaqueous electrolyte cells (such as lithium ion cells) is highly demanded, and ensuring high sealing functionality is essential in such fields.